The present invention relates generally to image processing systems, and more particularly to such image processing systems for displaying, recording and reproducing a high-grade image such as HDTV and 35-mm picture film.
As a system for treating a high-grade and high-resolution image there is known a display apparatus such as a 35-mm or 70-mm picture projector. For the treatment-facilitating purposes and picture-deterioration preventing purposes, for such a display apparatus there is developed a device for reading an image on a film to convert the film picture into an image signal such as a HDTV to record it in a digital VTR (video tape recorder).
FIG. 10 is an illustration of one example of conventional image-reading techniques of the types of scanning a line sensor with light to read a film picture. In FIG. 10, designated at numeral 902 is a line sensor disposed at one side of a film 900 to be elongated in a main scanning direction F900 of the film 900 and denoted at numeral 904 is a light source disposed at the other side of the film 900 to be opposed relation to the line sensor 902 with the film 900 being interposed therebetween. The film 900 is illuminated with light emitted from the light source 904 and, at the same time, moved in a secondary scanning direction F902 perpendicular to the main scanning direction F900, whereby the image information of the film 900 can be read out by means of the transmission light from the light source 904 to the line sensor 902. The line sensor 902 photoelectrically converts the incident transmission light into electric charges. Then, the charges in the line sensor 902 are successively shifted in a direction F904 (the main scanning direction F900), thus obtaining a signal having a waveform as illustrated at numeral S900. This operation is effected in conjunction with movement of the film 900 in the secondary scanning direction F902 and hence the film image can entirely be converted as an image signal into an electric signal.
Secondly, a description will be made hereinbelow in terms of one example of conventional reproducing techniques for reproducing the image converted into the image signal. FIG. 11 shows a conventional reproducing technique of the type of using a linearly (one-dimensionally) arranged light-emitting elements. In FIG. 11, designated at numeral 910 is a shift register responsive to a clock signal and an image data signal corresponding to the film picture. The image data for one line is latched by a latch circuit 912 at the timing of a latch signal, whereby an LED (light-emitting diode) array 914 is driven in correspondence with the latched image data. Light emitted from the LED array 914 is incident through a scanning galvanomirror 916 and a writing lens 918 on a spatial light modulator 922, thereby writing the image data for one line. Here, the spatial light modulator comprises an optical conductive layer and a light modulating layer, the optical conductive layer having a conductive characteristic variable in accordance with information-writing light so as to apply an electric field corresponding to the intensity distribution of the writing light to the light modulating layer to thereby modulate reading light incident on the light modulating layer. If repeatedly performing this writing operation with the galvanomirror 916 being rotated, the image information for one screen can be written therein. This image information is wholly read out by reading light incident from a reading light source 926 through a polarization beam splitter 924 on the spatial light modulator 922 and then projected through a projecting lens 928 onto a screen 930.
However, such conventional techniques can arise the following problems. That is, in the case of the image reading based on the line sensor, since the electric signal due to the photoelectric conversion is arranged to be successively transferred and outputted in the direction F904, the image reading speed is restricted by the signal transferring speed. While the transfer clock frequency for the register of the line sensor is generally several MHz to several 10 MHz, as a result it becomes impossible to read and output the image such as 35-mm or 70-mm film motion picture with a high resolution in real time. For eliminating this problem, two rows of registers 932 and 934 are provided as illustrated in FIG. 12 so that the photoelectric conversion signals of the odd-number elements of a line sensor 936 are transferred to the register 932 through a transfer gate 938 to which is inputted a gate signal indicative of the operation timing and the photoelectric conversion signals of the even-number elements of the line sensor 936 are transferred to through another transfer gate 940 to the register 934. The respective photoelectric conversion signals transferred to the registers 932 and 934 are outputted through a signal charge detecting section 942. However, this system can arise a disadvantage in efficient coding operations such as compression and expansion because the image data exist at random. Thus, the image data are required to be once converted into the serial data for processing and hence difficulty is encountered to perform the processing at a high speed. Such a disadvantage similarly occurs in the case of the image writing due to the LED array. That is, the transfer clock frequency of the shift register 910 is actually about 10 MHz, and therefore, when treating the image data corresponding to 4000 pixels in the horizontal direction, the time required for transferring the image data up to the end of the register becomes about 0.4 ms. In addition, if one screen corresponds to 2300 lines, the time taken for writing the image data for one screen becomes 920 ms, thereby making it difficult to treat a motion picture. Particularly, in the case of processing and recording or reproducing an image such as a 70-mm film picture with a high resolution, the aforementioned serial data conversion causes the high-speed processing to become more difficult so as not to allow the real-time processing.
On the other hand, the compression processing and the like becomes weighty for the recording and transmission of the image data in accordance with increasing tendency in the resolution of the image. In this case, the image data are preferable to be seriated in terms of the adjacent pixels. As an image processing system where the image data are seriated there is known a multi-display system. However, this multi-display system has the problem that image joints appear between the displays.